Monographs Details: Fissidens guianensis Mont. var. guianensis
Authority: Pursell, Ronald A. 2007. Fissidentaceae. Fl. Neotrop. Monogr. 101 (Published by NYBG Press)
Family:Fissidentaceae
Synonyms:Fissidens guianensis Mont., Fissidens guyanensis Mont., Fissidens corticola Schimp., Fissidens stipitatus Ångstr., Fissidens cataractarum Demaret & P.de la Varde
Description:Variety Description - Plants light to sordid green. Stems monomor-phic, unbranched and branched, to 9.0 mm long x 2.5 mm wide; rhizoids basal and axillary, smooth, reddish; axillary hyaline nodules absent; epidermis and outer 1-2 tiers of cortical cells small, incrassate, pigmented; inner cortical cells larger, thin-walled, hyaline; central strand present or absent. Leaves crispate, somewhat inrolled from tips when dry, loosely imbricate, as many as 22 pairs, oblong, obtuse to rounded, sometimes apiculate, to 1.3 mm long x 0.3 mm wide; margin serrulate-crenulate, Embate and ± entire on proximal 1/2 or less of vaginant laminae of most leaves, marginal or intralaminal, limbidial cells unistratose; costa ending 2-4 cells below leaf apex, bryoides type; dorsal lamina rounded to truncate at insertion, not decurrent; vaginant laminae of cauline leaves ± 1/2-2/3 leaf length, acute, slightly unequal; laminal cells ± obscure, eguttulate, unistratose, firm-walled, pluripapillose, quadrate to rounded-hexagonal, 4-7 µm long. Monoicous (gonioautoicous, rhizautoicous, cladautoicous); perigonia gemmiform and axillary or terminal on short stems around bases of perichaetial stems or terminal on main stems and branches; perichaetia terminal on main stems and branches. Sporophytes 1-2 per perichaetium; seta yellow, darkening with age, to 3 mm long; theca exserted, erect, radially symmetric to inclined, bilaterally symmetric, to 0.8 mm long, stomatose, exothecial cells quadrate to oblong, vertical walls thicker than horizontal walls, collenchymatous; peristome scariosus type; operculum conic, long-rostrate, 0.5 mm long. Spores finely papillose, 9-13 µm diam. Calyptra cucullate, smooth, 0.5 mm long, covering only the rostrum.

Discussion:Fissidens guianensis var. guianensis is distinguished by its obtuse to rounded leaves, a short limbidium on the vaginant laminae of all leaves except perhaps the lowermost of both fertile and infertile stems, and small, pluripapillose laminal cells. The variety can be confused with F. pallidinervis, but the presence of the limbidium on all but the smallest leaves in the former species, rather than on only the perichaetial and subtending leaves, will distinguish it from the latter species. Often, however, the limbidium is greatly reduced, consisting of only a few elongate cells at the proximal end of the vaginant laminae and can be easily overlooked. Usually the costa of F. guianensis ends closer to the leaf apex than it does in F. pallidinervis.
Distribution:Risaralda Colombia South America| Saint-Laurent-du-Maroni French Guiana South America| Trinidad and Tobago South America| Dominica South America| Chiapas Mexico North America| Jalisco Mexico North America| Nayarit Mexico North America| Yucatán Mexico North America| Petén Guatemala Central America| Toledo Belize Central America| Atlántida Honduras Central America| Copán Honduras Central America| Yoro Honduras Central America| Alajuela Costa Rica Central America| Cartago Costa Rica Central America| Puntarenas Costa Rica Central America| Bocas del Toro Panamá Central America| Darién Panamá Central America| Panamá Panama Central America| La Habana Cuba South America| Piñar del Río Cuba South America| Santiago de Cuba Cuba South America| Portland Jamaica South America| Trelawny Jamaica South America| El Seibo Dominican Republic South America| La Altagracia Dominican Republic South America| La Vega Dominican Republic South America| Puerto Rico South America| Amazonas Colombia South America| Antioquia Colombia South America| Cauca Colombia South America| Chocó Colombia South America| Tolima Colombia South America| Amazonas Venezuela South America| Bolívar Venezuela South America| Falcón Venezuela South America| Lara Venezuela South America| Sipaliwini Suriname South America| Cayenne French Guiana South America| Los Ríos Ecuador South America| Napo Ecuador South America| Loreto Peru South America| Madre de Dios Peru South America| San Martín Peru South America| Saint Thomas Virgin Islands of the United States South America| Saint Lucia South America|